The female threads are machined too large on these unions. If you take a 1/2" nipple you can screw it into the union with just your fingers and bury the threads. You can shake the 1/2" nipple and the half of the union will rattle on the nipple. That's how oversized the threading is. Additionally about an 1/8" of the nipple will protrude past the mating surface of the two halves of the union. This prevents the two surfaces of the union from meeting and forming a compression seal. I purchased two of these unions on my order and both of them were the same way on both sides of the union. I would challenge Signature Hardware to actually check their inventory and send these unions back to their supplier. P.S. just to cover all the bases I checked the 1/2" IPS chrome nipples I used with these unions on a 1/2" FIP threaded valve as well as a 1/2" FIP lug EL to make sure the fault lay with the union and not with the nipple going into the union.

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